U.S. Pat. Nos. 3,194,452 and 3,847,370 describe tube stripping clamps which have internal rollers. These clamps are primarily useful for pulling along a flexible tube to strip out its contents. Such clamps are not useful for one-handed operation for pushing the contents out of such tube. Such pushing action would simply buckle the tube.
U.S. Pat. No. 3,099,429 describes a typical roller clamp in which a firm actuated roller and floor of the clamp are inclined toward each other to vary the flow rate of liquid through such tube. Such roller clamps remain basically stationary on the tube and do not act to strip out the tube's contents by longitudinal rolling action along the tube.
In a co-pending co-owned application entitled "Blood Sampler," Ser. No. 025,980, filed Apr. 2, 1979, a flexible tube blood collector is described which is used to dispense a blood sample into a testing machine. Also in a co-pending, co-owned application entitled "Method of Collecting and Dispensing A Blood Sample," Ser. No. 025,979, filed Apr. 2, 1979, the method is described and claimed. When the machine does not have a vacuum extractor for the blood sample, the blood sample must be stripped from the tube into the machine. Because the stripper clamp is moving with a pushing action, it is important not to buckle the tube as the clamp proceeds toward the machine. Previous stripper clamps required a two-handed stripping; i.e., one to hold the tube taut to prevent buckling and the other to slide the clamp.